Besides the fact that on android, the app requires what appears to be every single permission, be aware that all companies dealing in media have a designated Party official liaison who usually sits in the office and has more decision power than the editor in chief.

Based on my experience working and developing in China, I would say I can all but guarantee that the Chinese government is viewing and editing all data as it pertains to wechat. All chatlogs, all private conversations, all financial transactions, all GPS coords for checkin locations, all of it. They may not be doing anything with it, but it's being stored.